Mountain Hardwear HyperLamina Spark 35 Sleeping Bag - Ginkgo Left Hand Long. Highest performance synthetic bag on the market. Thermally mapped insulation and half-length center zip maximize efficiency. Engineered to be the lightest and warmest synthetic bag on the market. Lamina construction welds the Thermal.Q insulation to the shell and lining, eliminating the cold spots caused by traditional stitching. By mapping different insulation weights throughout the top of the bag we are able to...